The present invention relates to apparatus and a method for separating a heavier liquid and a lighter liquid. In one aspect, the invention relates to apparatus for separating a heavier liquid, a lighter liquid and a gas.
It is often necessary to separate mixtures of lighter and heavier liquids. For example, the effluent from hydrocarbon processing reactors often contains a heavier aqueous liquid and a lighter hydrocarbonaceous liquid, which are relatively immiscible. In addition, reactor effluents often contain a vapor or gas. It is desirable to separate the aqueous material from the hydrocarbonaceous material and to separate gas from the liquids to facilitate further processing of the hydrocarbonaceous material, and to permit recycle of hydrogen in the gas.
Various configurations of separation equipment have been suggested and used commercially for separating mixture of lighter and heavier liquids. For example, in one system, a mixture of lighter and heavier liquids and gases is introduced into one end of a horizontal, elongated vessel. A longitudinal settling chamber extends along the bottom of the vessel from a point near the inlet to the other end of the vessel. The settling chamber is closed off from the major portion of the vessel's interior, but has an opening into the major portion of the interior near the mixture inlet. This opening is normally filled by a fluids-permeable coalescing pad. In a separator of this type, most of the gas separates from the liquids and is withdrawn from the major portion of the interior of the vessel before the mixture of liquids enters the settling chamber. After passing through the coalescing pad into the chamber, liquids flow along the length of the chamber while separating into an upper lighter phase and a heavier lower phase. Typically, the lower phase is an aqueous liquid and the upper phase is a hydrocarbonaceous liquid. These two phases are then separately withdrawn from the vessel, the lighter hydrocarbonaceous liquid being removed from the chamber through the end wall of the vessel, and the heavier aqueous liquid through the bottom of the vessel.
Heretofore, it has been difficult to obtain a satisfactory separation of a hydrocarbonaceous liquid from an aqueous liquid when the viscosity of the hydrocarbonaceous liquid is high and the density of the hydrocarbonaceous liquid is relatively close to that of the aqueous liquid. The difficulty of making such a separation has resulted in the use of undesirably large, complex and expensive separation equipment. Separators previously suggested include numerous baffles, chambers, conduits and the like. The apparatus and method of the present invention permit liquid mixtures, such as oil-water mixtures, to be easily and economically separated. The present invention further optionally provides for separation of gases which may be present in admixture with such liquids.